Is it possible to set material of one face only in Blender 2.45 (old version)?
Yes, from the Editing Panel

In Blender 2.45 the button to assign a material to faces can't be found in the Shading Panel under the Material section like depicted in your image.

It is instead disjoined from the Material's editor (where you edit material's parameters) but linked to the the mesh itself, and so grouped with the sections that are about face's properties like shading, editing tools...

You can see the section in the lower left of the following image.



You can find more information in the official documentation.